1. Field of the Invention
This invention relates to a wire processing structure for lead wires.
2. Description of the Related Art
JP-A-61-136294 discloses a construction in which one ends of wires are soldered respectively to copper foil portions on a printed circuit board, and the other ends of the wires are connected to an electrical mechanism part fixedly secured to the printed circuit board, and an intermediate portion of each wire is fixed to one of a plurality of juxtaposed slits formed in the printed circuit board, and by adopting this means, variations in length of the wires are absorbed, thereby preventing the slackening of the wires.
On the other hand, JP-A-62-168685U discloses a wire processing which is effected by a structure shown in FIG. 3. In this wire processing structure, lead wires 10, soldered at their one ends respectively to lands 2 on a printed circuit board 1, are passed through a narrow, elongate slot or slit 3 formed through that portion of the printed circuit board 1 disposed near to the lands 2. An end portion 4 of the slit 3 is formed into a step-shape. As will be appreciated from FIG. 3, the slit 3 has a width H1 and a width H2 which are larger than a wire width of the wire 10, and the withdrawal of the wires, passed through the slit 3, is prevented by the step-shaped end portion 4 of the slit 3.
However, although the technique, disclosed in JP-A-61-136294, is effective when variations in length of the wires are very small, and for example, are within the tolerance range, it cannot deal with the problem when the length variation range is wide.
With respect to the technique disclosed in JP-A-62-168685U and described with reference to FIG. 3, when the other ends of the wires 10 are connected to an electrical part mounted on a movable member, the swaying movement of the wires 10, following the movable member, is transmitted to the soldered portions of the lands 2 since the width (H1 and H2) of any portion of the slit 3 is larger than the wire width of the wire 10, and as a result there are high possibilities that the wires 10 are cut and that the lands 2 are separated from the printed circuit board. And besides, the withdrawal of the wires 10, passed through the slit 3, is prevented merely by the step-shaped end portion 4 of the slit 3 having the width H2 slightly larger than the wire width, and therefore there is a possibility that the withdrawal prevention effect is not satisfactorily achieved. Furthermore, when soldering the one end of the wire 10, passed through the slit 3, to the land 2, the wire 10 can move in the slit, so that the soldering operation can not always be carried out easily.
This invention has been made under the above circumstances, and an object of the invention is to provide a lead wire-processing structure in which when the lead wires are too long, the lead wires can be installed or arranged in an orderly manner while absorbing excess-length portions of these wires.
Another object of the invention is to provide a lead wire-processing structure in which when one end of each lead wire is soldered to a land on a wiring board, and when the other end of the lead wire sways, effects of this swaying movement will not be transmitted to the soldered portion.
A further object of the invention is to provide a lead wire-processing structure in which even when the lead wires are connected to an electrical part mounted on a movable member, the movement of the movable member can be effectively absorbed by the flexible deformation of the lead wires.
A still further object of the invention is to provide a lead wire-processing structure in which the lead wires will not be taken apart.
According to the present invention, there is provided a lead wire-processing structure CHARACTERIZED in that lead wires are soldered at their one ends respectively to lands formed on one side of a wiring board while the other ends of the lead wires are connected to an electrical part; and those portions of the lead wires, disposed in the vicinity of the one ends thereof, are extended respectively from the lands in generally contiguous relation to the one side of the wiring board, and are passed through a slit-like, U-shaped notch formed in the wiring board; and that portion of each of the lead wires, extending from the U-shaped notch on the other side of the wiring board, has a loop portion formed between a U-shaped notch-passing portion of the lead wire, passed through the U-shaped notch, and that portion of the lead wire connected to the electrical part; and the loop portions are loosely fitted on a projected piece portion of the wiring board disposed adjacent to the U-shaped notch.
In this construction, when the lead wires are too long, the radius of curvature of the loop portions can be increased and decreased, and the number of turns of each loop portion can be increased and decreased, and by doing so, the wires can be processed in an orderly manner in accordance with the excess-length portions of the lead wires. And besides, when the other ends of the lead wires sway, the loop portions satisfactorily perform the function of absorbing this swaying movement, and therefore effects of the swaying movement of the other ends of the lead wires will not be transmitted to the one ends of the lead wires. Furthermore, those portions of the lead wires, disposed in the vicinity of their one ends 11 soldered respectively to the lands on the one side of the wiring board, are extended in generally contiguous relation to the one side of the wiring board, and are passed through the U-shaped notch 130, and this arrangement also serves to prevent the effects of the swaying movement of the lead wires from being transmitted to the soldered portions.
Preferably, that portion of each of the lead wires, extending between the U-shaped notch-passing portion thereof and the loop portion thereof, is extended in generally contiguous relation to the other side of the wiring board. With this construction, the lead wires can be easily extended in an orderly manner.
The electrical part can be mounted on a movable member which is spaced from the other side of the wiring board in opposed relation thereto, and is reciprocally movable in a predetermined path. Alternatively, the electrical part can be mounted on a movable member which is spaced from the other side of the wiring board in opposed relation thereto, and is reciprocally movable toward and away from the other side of the wiring board in a path. The electrical part is, for example, a drive motor for a so-called DVD. Therefore, the lead wire-processing structure of the invention can be suitably used for connecting an electrical circuit of the wiring board to the DVD drive motor.
Preferably, an engagement piece portion for preventing the withdrawal of the loop portions is formed on the projected piece portion, and projects in a direction perpendicular to a direction of projecting of the projected piece portion. With this construction, the loop portions will not be withdrawn from the projected piece portion, and therefore will not be taken apart.
Preferably, the U-shaped notch has an inlet/outlet portion for the lead wires, and a passage portion through which the lead wires are passed, the passage portion being continuous with the inlet/outlet portion, and a width of the inlet/outlet portion is smaller than a width of the passage portion, and is substantially equal to a width of the lead wire. With this construction, the lead wires, passed through the passage portion of the U-shaped notch, are less liable to be withdrawn from the U-shaped notch.
In the invention, the relation between the width of the inlet/outlet portion of the U-shaped notch and the wire width of the lead wire is suitably determined, thereby preventing the lead wires from being withdrawn from the U-shaped notch. The one ends of the lead wires, passed through the passage portion of the U-shaped notch, are soldered to the lands, respectively, and therefore when effecting this soldering operation, the lead wire, passed through the passage portion of the U-shaped notch, can be slightly pulled from the passage portion so that the soldering operation can be effected easily.
Preferably, the lands, the passage portion of the U-shaped notch and the projected piece portion are arranged in a juxtaposed manner along an edge of the wiring board. With this arrangement, the lead wires can be extended in an orderly manner along the edge of the wiring board.